The Invasive Plant is Toxic to Birds
Nandina (Nandina domestica), also known as heavenly bamboo, is anything but heavenly. And, it actually is not related to bamboo. Nandina is a small Asian shrub, which has been known for years to be invasive. But, recent research has proved that the consumption of its berries can be deadly to birds. Unfortunately, this plant frequently is planted in landscapes by homeowners or landscaping companies, because of its evergreen foliage, fall color and red berries.
Nandina is listed as invasive on many of the Southeastern states’ lists of pest plants. One factor is the berries; they are eaten by birds, which causes seedlings to pop up naturally. Additionally, nandina is shade-tolerant, allowing it to invade woodlands and forests, where it outcompetes native vegetation. In addition to spreading by seed, it also may colonize by underground runners. According to the University of Florida Center for Aquatic and Invasive Plants, nandina regenerates from root fragments, making it difficult to eradicate.
The University of Georgia has been instrumental in establishing that nandina berries are toxic to birds. The university’s involvement began in the spring of 2009, when many dead cedar waxwings (Bombycilla cedrorum) were found in Thomas County. Examination of the dead birds by Tifton Veterinary Diagnostic and Investigational Laboratory determined that the cedar waxwings had partially digested nandina berries in their gastro-intestinal tracts. The laboratory found that their deaths were due to cyanide poisoning, and nandina berries could contain large amounts of cyanogenic compounds, which also are poisonous to children, cats, dogs and other animals.
Cedar waxwings may be especially prone to this poisoning, because they feed almost exclusively on fruits, often eating large quantities at a time. The bright red berries of the nandina plant are quite attractive to birds, especially when food supplies are low during winter and early spring. In addition to cedar waxwings, birds such as bluebirds, robins and mockingbirds are frequent fruit eaters, so these species also are at risk from nandina poisoning. You can read more about toxicity in cedar waxwings from the UGA College of Veterinary Medicine at https://bit.ly/2Zwg19D.
If you have a nandina plant in your garden, especially one that sets fruit, you should eliminate it, to minimize the problems it poses to the environment. In the meantime, remove any berries, to prevent the harmful spread of this noxious plant, and help protect birds.
Small nandina seedlings often can be hand-pulled, so keep watch in your yard. Act quickly when dealing with seedlings, as larger specimens have to be dug out of the ground, removing any root fragments to prevent reinfestation. Frequent cutting or mowing may weaken the plant enough to control it, though it might pop up from underground runners. Chemicals such as glyphosate or triclopyr can be applied to cut stems for more effective control.
If you must have nandina in your garden (and I hope you don’t!) you can consider planting some of the dwarf cultivars that rarely bloom or set fruit. If you take this route, keep an eye on your plants, to be sure that they behave as advertised.
– Mary Tucker is a North Carolina native who has lived in Cherokee County for more than 25 years. She is a Lifetime Master Gardener whose special interest is gardening with native plants.